OUTLINE: This is a multicenter study. Patients receive leucovorin calcium IV over 2 hours followed by fluorouracil IV over 24 hours on day 1 followed by gemcitabine IV over 80-150 minutes on day 2. Treatment repeats every 2 weeks for a minimum of 6 courses in the absence of disease progression or unacceptable toxicity. Patients achieving complete response may continue chemotherapy for up to 1 year. Patients with locally advanced disease after 3 months of chemotherapy may receive concurrent radiotherapy with chemotherapy for 5 weeks, or may undergo surgical resection. Fluorouracil-based chemotherapy (with or without radiotherapy) may then resume after surgery. Patients are followed for survival.